(Source: FGDC, USGS (21 March, 2003). Content Standard for Digital Geospatial Metadata (CSDGM). Retrieved February 2, 2004. http://www.fgdc.gov/metadata/contstan.html .)
The Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) was developed from the perspective of defining the information required by a prospective user. This includes such information as determining the availability of a set of geospatial data, determining the fitness of the set of geospatial data for an intended use, determining the means of accessing the set of geospatial data, and successfully transferring the set of geospatial data. As such, the standard provides a common set of terminology and definitions for the documentation of digital geospatial data. The standard establishes the names of data elements and compound elements (groups of data elements) to be used for documentation, the definitions of these compound elements and data elements, and the information about the values that are to be provided for the data elements. The standard does not specify the means by which this information is organized in a computer system or in a data transfer, nor the means by which this information is transmitted, communicated, or presented to the user.
Specialist meetings on geospatial metadata began in 1992 and led to an initial version of the Content standard in 1994. The International Standards Organization (ISO) TC211 used this as its starting point for developing an international standard (19115, see section 4.2). By Executive Order 12906, signed on April 11, 1994, all Federal agencies "shall document all new geospatial data it collects or produces using the standard under development by the FGDC." FGDC finalized a revised version of its standard in 1998, which "is thought to be consistent with" the emerging ISO draft standard, and allows for discipline-specific profiles of the generic metadata content. FGDC will adopt ISO's 19115 standard when it becomes final in early 2002.
CSDGM Version 2 allows geospatial data communities to develop "profiles" of the base standard. Many of these profiles have extended the base standard by adding metadata elements to meet their specific community metadata requirements. In particular, a proposed set of Extensions for Remote Sensing Metadata recently underwent public review.
The standard structures metadata along seven topics:
- Identification Information -basic information about the data set. Examples include title, geographic area covered, currentness, and rules for acquiring or using the data.
- Data Quality Information -an assessment of the quality of the data set. Examples include positional and attribute accuracy, completeness, consistency, sources of information, and methods used to produce the data.
- Spatial Data Organization Information -the mechanism used to represent spatial information in the data set. Examples include the method used to represent spatial positions directly (such as raster or vector) and indirectly (such as street addresses or county codes) and the number of spatial objects in the data set.
- Spatial Reference Information -description of the reference frame for, and means of encoding, coordinates in the data set. Examples include the name of and parameters for map projections or grid coordinate systems, horizontal and vertical datum, and the coordinate system resolution.
- Entity and Attribute Information -information about the content of the data set, including the entity types and their attributes and the domains from which attribute values may be assigned. Examples include the names and definitions of features, attributes, and attribute values.
- Distribution Information -information about obtaining the data set. Examples include a contact for the distributor, available formats, information about how to obtain data sets online or on physical media (such as cartridge tape or CD-ROM), and fees for the data.
- Metadata Reference Information -information on the currentness of the metadata information and the responsible party.
For a detailed description of FGDC CSDGM, please go to the FGDC website.